DESCRIPTION: It is proposed to develop an innovative technology for the immediate and accurate diagnosis of pneumothorax. An actuator-sensor pair operating in the acoustic audible frequency range are connected to a computer that will immediately report the presence or absence of acoustic changes consistent with a diagnosis of pneumothorax. We anticipate that the final product(s) will be both inexpensive and portable. This technology may lead to a substantial decrease in mortality, morbidity and health care costs associated with pneumothorax. Phase 1 research will test feasibility in a dog model. PROPOSED COMMERCIAL APPLICATION: The proposed device would have major commercial potential with possible purchase by emergency departments, intensive care units, military medical units, airlines and ambulances.